Skin cancer is the most common cancer in the United States and its numbers are increasing. Deaths from skin cancer are due mostly to melanoma, whose numbers are also increasing. Thin melanomas (less than 1 mm in thickness) removed by surgery are associated with normal life, but thicker melanomas (more than 4 mm) are considered to have already spread to lymph nodes or distant organs, and cannot be cured by available treatments. Having discovered melanoma to contain molecules preventing the immune system from killing the tumor, we will study how to counteract these molecules so the immune system can better fight this deadly cancer.